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POWERD(8)               FreeBSD System Manager's Manual              POWERD(8)

NAME
     powerd - system power control utility

SYNOPSIS
     powerd [-a mode] [-b mode] [-i percent] [-n mode] [-p ival] [-P pidfile]
            [-r percent] [-v]

DESCRIPTION
     The powerd utility monitors the system state and sets various power
     control options accordingly.  It offers three modes (maximum, minimum,
     and adaptive) that can be individually selected while on AC power or
     batteries.

     Maximum mode chooses the highest performance values.  Minimum mode
     selects the lowest performance values to get the most power savings.
     Adaptive mode attempts to strike a balance by degrading performance when
     the system appears idle and increasing it when the system is busy.  It
     offers a good balance between a small performance loss for greatly
     increased power savings.  The default mode is adaptive.

     The powerd utility recognizes the following runtime options:

     -a mode           Selects the mode to use while on AC power.

     -b mode           Selects the mode to use while on battery power.

     -i percent        Specifies the CPU idle percent level when adaptive mode
                       should begin to degrade performance to save power.  The
                       default is 90% or higher.

     -n mode           Selects the mode to use normally when the AC line state
                       is unknown.

     -p ival           Specifies a different polling interval (in
                       milliseconds) for AC line state and system idle levels.
                       The default is 500 ms.

     -P pidfile        Specifies an alternative file in which the process ID
                       should be stored.  The default is /var/run/powerd.pid.

     -r percent        Specifies the CPU idle percent level where adaptive
                       mode should consider the CPU running and increase
                       performance.  The default is 65% or lower.

     -v                Verbose mode.  Messages about power changes will be
                       printed to stdout and powerd will operate in the
                       foreground.

SEE ALSO
     acpi(4), apm(4), cpufreq(4)

HISTORY
     The powerd utility first appeared in FreeBSD 6.0.

AUTHORS
     Colin Percival first wrote estctrl, the utility that powerd is based on.
     Nate Lawson then updated it for cpufreq(4), added features, and wrote
     this manual page.

BUGS
     The powerd utility should also power down idle disks and other components
     besides the CPU.

     If powerd is used with power_profile, they may override each other.

     The powerd utility should probably use the devctl(4) interface instead of
     polling for AC line state.

FreeBSD 11.0-PRERELEASE        November 6, 2005        FreeBSD 11.0-PRERELEASE

NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | HISTORY | AUTHORS | BUGS

Want to link to this manual page? Use this URL:
<https://www.freebsd.org/cgi/man.cgi?query=powerd&sektion=8&manpath=FreeBSD+7.0-RELEASE>

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